Methods and systems for operating and NGL recovery process are provided. In an exemplary method, an absorber column upstream of a fractionator column is operated at a higher pressure than a pressure in the fractionator column. An NGL (C.sub.3 plus) stream is taken from the bottom of a fractionator column and then ethylene/ethane stream is taken from the top of the fractionator column. A differential pressure between the absorber column and the fraction are column is controlled based, at least in part, on a flow rate of the fractionator feed stream from the absorber column to the fractionator column.

The invention relates to a method (100) for the recovery of a separation product which contains predominantly hydrocarbons with two carbon atoms, with the use of a separation feedstock which contains predominantly methane, hydrogen and hydrocarbons with two carbon atoms, wherein the methane content of the separation feedstock is up to 20%, and the separation feedstock is provided in a gaseous state. It is provided that, at a first pressure level, the separation feedstock is partially condensed in a single step by cooling from a first temperature level to a second temperature level, thereby obtaining precisely one first liquid fraction and precisely one first gaseous fraction; at least one part of the first gaseous fraction is partially condensed in a single step through further cooling from the second temperature level to a third temperature level, thereby obtaining precisely one second liquid fraction and precisely one second gaseous fraction; at least one part of the second gaseous fraction at the second pressure level is subjected to a contraflow absorption in the contraflow to an absorption liquid containing predominantly methane, thereby obtaining precisely one third liquid fraction and precisely one third gaseous fraction; the first, the second and the third liquid fraction are at least partially combined and, at least partially, at a second pressure level above the first pressure level, subjected to a low-temperature rectification, thereby obtaining a sump liquid and an overhead gas; at least one part of the overhead gas at the second pressure level is partially condensed in a single step through further cooling from the second temperature level to the third temperature level, thereby obtaining a fourth liquid fraction and a fourth gaseous fraction; and the absorption liquid containing predominantly methane is formed through further cooling of at least a part of the fourth gaseous fraction to a fourth temperature level. A corresponding plant also forms the subject matter of the invention.

The invention relates to a process for the production of ethylene by oxidative dehydrogenation of ethane, comprising: a) subjecting a stream comprising ethane to oxidative dehydrogenation conditions, resulting in a stream comprising ethylene, unconverted ethane and light components; b) subjecting ethylene, unconverted ethane and light components from the stream resulting from step a) to distillation, resulting in a stream comprising ethylene and light components and a stream comprising unconverted ethane; c) optionally recycling unconverted ethane from the stream comprising unconverted ethane resulting from step b) to step a); and d) subjecting ethylene and light components from the stream comprising ethylene and light components resulting from step b) to distillation at a top column pressure which is higher than the top column pressure in step b), resulting in a stream comprising light components and a stream comprising ethylene.

The invention relates to the field of olefin oligomerization to obtain liner α-olefins, particularly to a method of separating olefin oligomerization products using an evaporator. The invention includes two embodiments of the method of separating the oligomerization reaction product streams. In accordance with the first embodiment of the invention, the oligomerization reaction product stream after the step of isolating an initial olefin is fed into an evaporator to the step of separating the oligomerization reaction product steam. In accordance with the second embodiment of the invention, the oligomerization reaction product stream after the step of isolating the initial olefin is separated into two streams, the first part of which is fed into the separation column, and the second part is fed into the evaporator. The invention allows to minimize a quantity of technological equipment contaminated by the by-product polymer.

Various illustrative embodiments of a system and process for recovering high-quality biomethane and carbon dioxide product streams from biogas sources and utilizing or sequestering the product streams are provided. The system and process synergistically yield a biomethane product which meets gas pipeline quality specifications and a carbon dioxide product of a quality and form that allows for its transport and sequestration or utilization and reduction in greenhouse gas emissions. The system and process result in improved access to gas pipelines for products, an improvement in the carbon intensity rating of the methane fuel, and improvements in generation of credits related to reductions in emissions of greenhouse gases.

A method for operating an integrated system for producing olefins may include contacting a hydrogenation feed with a first hydrogenation catalyst to produce a hydrogenated effluent, the hydrogenation feed including at least a portion of a first process effluent from a first olefin production process and at least a portion of a second process effluent from a second olefin production process. The hydrogenation feed may include at least hydrogen, ethylene, carbon monoxide, acetylene, methyl acetylene, and propadiene, and the first hydrogenation catalyst may be a hydrogenation catalyst having a temperature operating range of at least 40° C. The hydrogenated effluent may include methyl acetylene, propadiene, or both. The method may further include contacting at least a portion of the hydrogenated effluent with a second hydrogenation catalyst, which may cause hydrogenation of at least a portion of the methyl acetylene and propadiene to produce an MAPD hydrogenated effluent.

A facility and method for membrane permeation treatment of a feed gas flow containing at least methane and carbon dioxide that includes a compressor, a pressure measurement device, at least one valve, and first, second, third, and fourth membrane separation units for separation of CO.sub.2 from CH.sub.4 to permeates enriched in CO.sub.2 and retentates enriched in CH.sub.4, respectively. A temperature of the first retentate is adjusted at an inlet of the second membrane separation unit with at least one heat exchanger as a function of the measured CH.sub.4 concentration in such a way so as to reduce the determined difference.

Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

A transalkylation process co-feeds benzene at a relatively high proportion with C9+ aromatics in a feed stream to a transalkylation reactor. At lower proportions (≤5 wt %) of benzene, ring loss is greater for benzene than toluene and ring loss is increased by increasing the proportion of benzene in the feed stream. When the benzene is co-fed in a proportion sufficiently greater than 5 weight percent of the feed stream, ring loss is unexpectedly reduced.

A method for separating and refining 1-butene with a high purity and a high yield from a raffinate-2 stream. The method includes: feeding raffinate-2 to a first distillation column; obtaining heavy raffinate-3 from a lower part of the first distillation column; recovering an upper part fraction containing 1-butene from an upper part of the first distillation column; feeding the upper part fraction containing 1-butene to a second distillation column; recovering a first lower part fraction rich in 1-butene from a lower part of the second distillation column and light raffinate-3 from an upper part of the second distillation column. Heat of the upper part fraction recovered from the upper part of the first distillation column is fed to the lower part of the second distillation column through a first heat exchanger. Thus, 1-butene is obtained with high purity and high yield while maximizing an energy recovery amount by double-effect distillation.